Just throw us in the looney bin. In the realm of cubic inches, 500 is a figure reserved for tall-deck Rat motors and Cadillacs. Any notion of ascertaining that level of displacement out of a small-block-or even most big-blocks-is pure crazy talk.
Sanity and common sense aside, we're here to say that it can be done. In fact, it's already been done and here's the kicker: It's been done with a production LS2 block. The motor in question, built by the School of Automotive Machinists in Houston, kicks out 717 hp and 630 lb-ft on pump gas with a dinky 248/254 at 0.050 inch hydraulic cam. The best news is that this isn't some custom one-off build. Anyone can now assemble a 500ci LS-series motor using off-the-shelf parts.
The mastermind who makes it all possible is ERL Performance, best known for its handiwork in the import drag racing scene. In a high-boost world where displacement is at a premium, ERL has perfected the art of making tiny four-cylinder motors a bit less tiny with its innovate deck plates, essentially a slug of billet aluminum sandwiched between the block's deck surface and cylinder head. The added thickness affords a taller deck height and hence a longer stroke and more cubic inches. While it sounds more like an elaborate IED (improvised explosive device) than a viable engine technology, ERL's deck plate system has been proven time and again under the most grueling conditions. We're talking sub-150ci boosted four-bangers pushing close to 1,000 hp on production blocks.
Aware of ERL's credentials, engine builder extraordinaire and LS1 guru Judson Massingill of SAM asked the obvious question while at an industry trade show. "I saw that ERL was doing these amazing things with Imports and suggested that they should apply this same technology to V-8s," he recollects. "At the time, people were starting to really push the limits of the LS1 architecture, and a common problem with stroker motors was scuffing up the piston skirts as a result of pulling them too far out the bottom of the bores. I pointed out that since the cam is positioned so high in the LS2 block and because it has a 4.000-inch bore, they could get some serious displacement out of it with one of their deck plates. I really can't take any of the credit, because all I did was have one conversation with them and they took care of the rest. ERL's finished product is honestly some of the most beautiful machine work I have ever seen."
By increasing the LS2's deck height from 9.240 to 10.200 inches, ERL's Super Deck II block can swallow up a 4.500-inch stroke. Combined with a 4.202-inch bore, the result is 500 delicious cubes. Considering the Gen IV's bore spacing of 4.400 inches, that much bore may seem to push the envelope of strength on paper, but ERL has done its homework. "We use a Darton ductile iron sleeve, which is three times stronger than stock," explains Sean Ragains of ERL. "Also, our deck plate is designed so that when you torque down the head bolts, they apply clamping pressure right at the top of the cylinder sleeves instead of the deck surface. This directs pressure to a smaller surface area, which results in greater clamping force. The truss design of our deck plate also transmits loads below the deck surface and between the cylinder bores. The result of all this is an extremely strong block with excellent head gasket seal."
So just how much power can it handle? On a 200hp hit of spray, SAM's 500 cranked out 923 hp and 906 lb-ft on the dyno. Furthermore, while ERL suggests backing down to a 4.1250-inch bore on boosted or heavy nitrous applications, its customers are pushing out 1,500 hp in supercharged motors and 1,700 hp with turbos. That's staggering, to say the least, but there's more to ERL's setup than a deck plate, as we'll outline in this story. So enough babbling already and on with the build!
A 500ci LS motor!
717 hp and 630 lb-ft on pump gas
Price (short-block only)